Received February 27, 2013
Accepted March 22, 2013

Objective: It is thought that oral supplementation with antioxidants might reduce damage caused by reactive oxygen species in the seminal fluid, and as a consequence it increases the fertilizing capacity of spermatozoa due to improvement of sperm parameters. Methods: The aim of this research is to evaluate the effect of folic acid supplementation, by semen analysis, in 49 subfertile men with the median age being 35.3 years (±7.7). The experimental group (n= 23) received 5mg of folic acid daily and the control group (n= 26) received placebo, both groups were treated for three months. In order to confirm the condition of sub-fertility, two spermogram were performed with an interval of 15 days between the first and the second test. Moreover, sexual intercourse and masturbation abstinence were required for two to five days before collecting the semen samples (according to the WHO recommendations). Pre and post-intervention examination was performed in the same laboratory by two professionals, according to the WHO criteria, 1999. The chi-square test was applied for both groups. Results: There was no statistically significant improvement in any of the following parameters: concentration, motility, morphology and vitality of the spermatozoa. Conclusion: Folic acid treatment alone in doses of 5mg/day does not improve sperm parameters in sub-infertile men.